Jun 20 Evolution of HiFi

While I've seemingly been quiet here, at least in talking about music, I've been busy trying to determine where to take the hi-fi system as of late. I discovered a problem and I've recently come up with an intermediate solution.
For those that don't know me well, I enjoy listening to music in two primary locations: in my office and in our Salon de musique family room. Each of the two rooms contains important assets.
1. The office has my workstation where the media files are stored.
2. The family room uses the better loudspeakers and a more sophisticated hi-fi system.
A computer-based hi-fi system isn't atypical today. I'm currently taking analog audio from my computer and passing that into an integrated amplifier. That, in turn, drives two bookshelf speakers on either side of my head here in the office. I use iTunes to drive the music, available in varying qualities, from 256kbit MP3s to lossless files ripped at 750-800 kbits.
I used to stream music downstairs to an Aiport Express using a Toslink cable plugged into a rather clear-sounding digital to analog converter. This little box is magic, and in a future upgrade, it will find its way upstairs with the computer.
Needless to say, since upgrading to iTunes 8.1 (and unchanged in iTunes 8.2), I noticed some sound quality issues downstairs. The music, especially with certain types (say, solo violin) became strident and ugly. Extensive testing revealed the "bad" link was the Airport Express. That's not to say another cable might not have helped, but using the same cable, going directly from computer to DAC revealed correct-sounding music.
Some reading indicated it may be a problem with clock jitter.
I therefore upgraded the system from an Airport Express to a Mac mini computer. Because i fancied running the mini headless (without a monitor), and I want to keep the media on my main workstation in the office, I set up an auto-mounting function in Mac OS X Leopard called autofs. This auto-mounts the media volume from the workstation on the mini. I made a copy of the iTunes library on the mini. Now, when it plays music, it's "streaming" it over the network. The machine also goes to sleep and wakes up on a schedule. The jittery-problems have not surfaced.
The issue then becomes, "What's next?" Obviously, this solution needs maintenance (upgrading the library to the auxiliary mini). However some point to USB as a superior communications medium between the computer and the DAC. Wavelength Audio's products especially look enticing.
The iPhone works as a great remote control, operating volume, track selection, and start/stop.